A system provided with a terminal device and an image forming device is known. The image forming device shifts from a power saving mode to a normal operation power mode in a case of determining that a user of the terminal device is present within a first detection range while the image forming device is in the power saving mode. Further, the image forming device shifts from the normal operation power mode to an ultrasonic communication operation to emit ultrasonic waves for executing a communication with the terminal device in a case of determining that the user is present within a second detection range, which is narrower than the first detection range, while the image forming device is in the normal operation power mode.